Cancer health disparities related to race and ethnicity are among the most serious problems facing the US health care system. A recent Institute of Medicine report stated that such disparities are seen at every level of health care, from prevention to treatment and follow-up. This problem is acutely evident in the figures for colorectal cancer (CRC) among African Americans (AAs). According to the American Cancer Society, AAs have the highest CRC incidence and mortality of any ethnic/racial group. Indeed, CRC incidence and mortality are 15% and 43% higher among AAs than Whites, respectively. These disparities could be effectively reduced through greater AA participation in CRC screening and early detection. More importantly, due to the preponderance of CRC in AAs beyond the reach of the flexible sigmoidoscopy, increased adherence to colonoscopy among AAs will save lives. Although there is clear evidence that providing patients with someone to help them manage/navigate the health care system (i.e., patient navigation (PN)) is effective in helping them to complete cancer screening, very few hospitals provide PN for colonoscopy. The vast majority of hospitals in NYC are unable to provide PN for patients for whom colonoscopy is recommended, in large part because of the costs associated with professional-led PN. The proposed R-25E seeks to address this serious public health problem by investigating the success of training AAs who have undergone colonoscopy to serve as peer patient navigators to help others from their community complete CRC screening via colonoscopy. The proposed training plan is supported by seven distinct lines of evidence: 1) research indicating a 76-90% reduction in CRC mortality through colonoscopy, 2) the success of PN in increasing participation in health promotion, 3) data from the NYC Department of Health showing underuse of PN for colonoscopy, 4) research demonstrating increased credibility of peers in providing health information, 5) research on volunteer-led health education interventions, 6) the cost savings we found in our preliminary research on peer led PN (PPN) for colonoscopy, and 7) our success in promoting cancer screening and preventative health care practices in AA communities of New York City through our collaboration with community leaders and church groups. The overall goal of the proposed R-25E is to reduce CRC morbidity and mortality by increasing AA participation in colonoscopy in a cost effective way. This will be accomplished through three specific aims: 1) The development and implementation of a training program for Peer Patient Navigation (PPN) to increase participation of AAs in colonoscopy;2) The examination of the cost effectiveness of the PPN training program in completion of colonoscopy from the perspective of AAs for whom colonoscopy is recommended;and 3) The investigation of the relative cost effectiveness of the PPN training program from the perspective of hospitals.